Compressed air jack with safety latch



July 31, 1951 c. P. HARRIS 2,562,493

COMPRESSED AIR JACK WITH SAFETY LATCH Filed Oct: 6Q 1947 Patented July 31, 1951 OFFICE COMPRESSED AIR JACK WITH SAFETY LATCH Cecil P. Harris, Bessemer, Ala.

Application October 6, 1947, Serial No. 778,078

1 Claim.

This invention relates to a compressed air lifting jack with an automatic safety latch. It has for its main objects to provide such a jack that will be absolutely safe to use, highly efficient for its purpose, cheap to manufacture, simple in structure, convenient to use, and not liable to easily get out of order.

Lifting jacks now in general use in automobile filling stations and garages make it necessary for safety that a fixed support be placed under the axle of a car after it is raised for service, especially if the attendant gets under the axle. The present invention has a safety latch that operates automatically when the jack piston reaches its top position. Other advantages and objects will appear from the drawing and description.

By referring to the drawing part of this application, it will be observed that Fig. 1 is a plan view of the assembled jack; Fig. 2 is a View on line 2-2 of Fig. 1 part in section and part full; and Fig. 3 is an enlarged detail view on line 3-3 f Fig. 2 showing the latch member and spring for same, with latch in the holding or supporting position in full lines and in release position in broken lines.

Similar reference numerals refer to similar a parts throughout the several views.

: "Referring to the drawing in detail it will be seen that the jack comprises a main cylinder I with a cup type piston 2 having an integral extension 3 that forms a tube or smaller cylinder 4 with threads 5 in the face of its inner surface.

A second extension member 6 screws into the tube extension. This second extension member has a cap 1 for placing under and in contact with an automobile axle or other object to be lifted. Compressed air is supplied from a source (not shown) through a pipe 8 with a main conportion of the latch being supported on the top drain outlet in the side of the valve, the valve being a regular water line valve with a safety outlet for draining.

The various parts of the jack may be made of any material suitable for the purpose. Also may be made in different sizes and capacities.

While I have shown and described the preferred embodiment of my invention, I do not wish to limit same to the exact and precise details of structure, but reserve the right to make all modifications and changes so long as they remain within the spirit and scope of the following claim.

Having described my invention I claim:

A compressed air lifting jack of the character described comprising, a main supporting base, a cylinder integral with and mounted upon said base, a piston in said cylinder, a piston rod integral with the piston, said piston rod formed as a tube with screw threads in its inner wall face, a round solid member with screw threads in its outer wall, said solid member being of a size adapted to screw into the tube portion of the piston rod to the bottom thereof with a portion of the solid member extending outward and upward from said tube portion of the rod; a pipe connected to said base near the bottom of the cylinder and extending upward therefrom, a latch mounted on the top of said pipe, said latch consisting of a flat piece of metal positioned slidable horizontally adjacent the top of the cylinder, said piston rod having a slot around in its lower outer wall, a coil type spring mounted upon said slidable latch and set to normally urge the inner end of the latch into the slot in the piston rod when the slot is in register with the inner end of the latch, said latch having a handle adapted as means to manually pull the latch end from the slot; means for conveying compressed air from an independent source into said cylinder and under said piston.

CECIL P. HARRIS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,046,145 Budesheim Dec. 3, 1912 1,248,861 Holloway Dec. 4, 1917 1,550,254 Hewey Aug. 18, 1925- FOREIGN PATENTS Number Country Date 487,254 France June 28, 1918 

